Couldn't a quick entry app get the inbox item into omnifocus using a custom URI? Something like this
http://inik.net/omnifocus-uri-handler.
Last.fm has custom links on their site when you browse it with an iphone that will open up the last.fm iphone app (
http://blog.last.fm/2008/07/13/lastf...and-ipod-touch), so it should be possible.
I don't think this could work for audio, or pictures because of the app sandboxing, but I don't see any reason you couldn't get tasks in.
joshua